反应详情

Two grams (4.43 mmol) of 14 are weighed into a round bottomed flask. Then, in a fume hood, 25 mL (325 mmol) of trifluroacetic acid is added, and the flask is capped and stirred. The solid dissolves in about a minute. The mixture is stirred for 1 hour, at which time deprotection will be done (HPLC can be used as a check). The acid is evaporated on a rotary evaporator (use a trap) and the product is dissolved in 100 mL of methylene chloride. This is extracted twice with 100 mL of half to ⅔ saturated sodium bicarbonate solution. The aqueous layers are back-extracted once with ˜50 mL of methylene chloride and this is combined with the rest. The organic layer is dried over sodium sulfate twice and evaporated to give a brown solid. If desired, this material can be recrystallized by diluting a very concentrated solution in methylene chloride with methanol and cooling.

1. customthe flask is capped
2. dissolutionThe solid dissolves in about a minute
3. stirringThe mixture is stirred for 1 hour, at which time deprotection
4. customThe acid is evaporated on a rotary evaporator (use a trap)
5. dissolutionthe product is dissolved in 100 mL of methylene chloride
6. extractionThis is extracted twice with 100 mL of half
7. extractionThe aqueous layers are back-extracted once with ˜50 mL of methylene chloride
8. dry with materialThe organic layer is dried over sodium sulfate twice
9. customevaporated
10. customto give a brown solid
11. customthis material can be recrystallized
12. additionby diluting a very concentrated solution in methylene chloride with methanol
13. temperaturecooling